Reciprocating piston type gas compressor



Jan. 19, 1965 w. E. MICHENER RECIPROCATING PISTON TYPE GAS COMPRESSOR 3Sheets-Sheet 1 Original Filed June 23, 1961 INVENTOR.

ATTORNEYS.

Jan. 19, 1965 w. E. MICHENER 3,165,236

RECIPROCATING PISTON TYPE GAS COMPRESSOR Original Filed June 23, 1961 3Sheets-Sheet 2 INVENTOR. m1 3 M40- ATTORNEYS.

Jan. 19, 1965 w. E. MICHENER 3,156,236

RECIPROCATING PISTON TYPE GAS COMPRESSOR Original Filed June 23, 1961 3Sheets-Sheet 3 45 ma i?! 0 40 24 v 37 3% E as I 6 INVENTOR. j fi gwicawm/ ATTORNEYS.

United States Patent 3,166,236 RECIPROCATING PISTON TYPE GAS COMPRESSORWilliam E. Michener, Milwaukee, Wis., assignor to Vilter ManufacturingCorporation, a corporation of Wisconsin Original application June 23,1961, Ser. No. 119,069, now

Patent No. 3,131,856, dated May 5, 1964. Divided and this applicationAug. 9, 1963, Ser. No. 308,052 4 Claims. (Cl. 23030) by the constructionof such machines is facilitated and the V efliciency is enhanced.

It has heretofore been common commercial practice to utilize compressorshaving several stages each embodying a cylinder and a piston cooperatingwith a set of annular suction and discharge valves, and provided withcapacity control mechanism for opening selected suction valves in orderto unload the corresponding stages.

These valves are usually formed of relatively thin but durable sheetmetal and of large diameter since the suction valve of each stage orcompression unit ordinarily surrounds its cylinder adjacent to itsoutlet end and the discharge valve is located closely adjacent to butbeyond this cylinder end so as to reduce the clearance space to aminimum, and each of these valves is constantly urged toward closedposition by an annular series of helical compression springs. While thisgeneral type and arrangement of annular valves has long been in use, ithas been ditlicult to properly guide the same relative to their annularinlet and discharge ports while reducing the clearance spaces to aminimum, and .it was also quite tedious to apply and remove these priorvalve assemblages.

Then, too, the capacity control mechanisms of these prior assemblagesand which were adapted to lift the suction valves from their seats inorder to unload the compressor were also relatively complicated anddifiicult to inst-all; and these prior mechanisms were thereforerelatively unreliable in operation and required considerable attentionin order to maintain them in proper operating condition.

It is therefore an important object of the present invention to providesimple andeffective means for facilitating installation of such valvesand of the unloading devices associated therewith so as to insure mostefiicient functioning of these compressors with least attention.

Another important object of this invention is to provide far morereliable guiding of the annular plate valves of such gas compressors inorder to eliminate excessive clearance space and to maintain both theinlet and dis charge valves properly centralized relative to their seatsand ports.

A further important object of the invention is to provide a simplifiedand improved capacity control device and mechanism for transmittingmotion therefrom to the annular suction valve for the purpose ofinsuring most eifec tive unloading of the compressor.

Still another important object of the present invention is to provide animproved valving and unloading assemblage for gas compressors, wherebyvarious parts of these mechanisms may be readily pre-assembled and thedevices may be installed as complete units within the com- Patented Jan.19, 1965 pressor housings in proper relation to the individualcylinders. i

These and other more specific objects and advantages of the inventionwill be apparent from the following detailed description.

A clear conception of the features constituting the present improvementsand of the construction and operation of a typical multiple cylindercompressor embody ing the invention may be had by referring to thedrawings accompanying and forming a part of this specification whereinlike reference characters designate the same or similar parts in thevarious views.

FIG. lis a diagrammatic side view of a multi-cylinder piston type of gascompressor embodying four pairs of radial cylinders each having thereina piston reciprocable from a common crank shaft adapted to be revolvedby an electric motor;

FIG. 2 is an enlarged transverse approximately vertical section throughthe crankcase and through one of the cylinders and valve assemblages ofa compressor such as shown in FIG. 1, with one of the capacity controlunits illustrated in elevation;

FIG. 3 is a further enlarged longitudinal approximately vertical butfragmentary section taken carefully through one pair of adjoiningcylinders and through a portion of the corresponding capacity controlmechanism, the section being taken along the line 3-3 of FIG. 1;

FIG. 4 is a slightly reduced top view of one of the improved capacitycontrol units showing the same applied to sections through a pair of thecompressor cylinders along the line 4-4 of FIG. 3;

FIG. 5 is a transverse section through the capacity control unit orunloading device of FIG. 4, taken along the line 55 of FIG. 6; and

FIG. 6 is 'an approximately vertical section through the same capacitycontrol device, taken along the line 6- -6 of FIG. 4.

While the invention has been illustrated and described herein as havingbeen embodied in a particular type of gas compressor especially adaptedfor refrigeration service and embodying eight reciprocable motor drivenpistons, it is not intended to necessarily confine the use of theimprovements to such a compressor; and it is also contemplated thatspecific descriptive terms employed herein be given the broadestpossible interpretation consistent with the disclosure.

Referring to FIGS. 1, 2 and 3 of the drawings, the gas compressorillustrated therein comprises in general; a main frame 9 having thereina suction chamber 10 communicating with a crankcase .10 in whichalcrankshaft 11 is revolvable by an electric motor 12; four pairs ofcylinders 13 mounted in the frame 9 and radiating from the axis of thecrankshaft 11; a piston 14 reciprocable within each of the cylinders 13by a connecting rod 15 attached to the crankshaft 11; an annular suctionvalve 16 surrounding the outer end of eachcylinder ,13-and coacting withinlet ports 17 which are communicable with the suction chamber 10 andwith the adjacent piston displacement chamber 18; an annular dischargevalve 19 coacting with an annular series of outlet ports 20 whichcommunicate with the adjacent chamber 18 of each cylinder 13 through ahead 21; a cover 22 enclosing each pair of heads 21 and communicatingwith a common compressed gas discharge space 23; and a capacity controlunit 24 cooperable with selected pairs of cylinders 13 and beingoperable to lift the suction valves 16 thereof in order to unload thecompressor.

The main frame is preferably formed of a sturdy integral casting andwhen the compressor is motor driven as shown in FIG. 1, the motor 12 andframe 9 may be mounted upon a foundation base 26 as illustrated. Eachcylinder 13 is provided with an integral flange 27 at :29 as in FIG. 3,and which has an annular series of small helical compression springs 30confined therein and coacting with the adjacent plate valve 17. Eachcylinder closure end head 21 is secured to another removable an- 'nularguard 31 by a bolt 32 as depicted in FIGS. 2 and 3,

I and each of these guards also confines an annular series of smallhelical compression springs 33 which coact with the adjacent plate valve19. Each discharge valve guard 31 and cylinder head 21 is normally heldwithin and in snug engagement with the adjacent normally stationarysuction valve guard 28'by means of a large and strong helical spring 34reacting against the adjacent cover 22; and these covers are detachablysecured to the frame 9 by cap screws 35.

It is important (that the periphery of each annular suction valve 16cooperates with its guard 28 with minimum clearance and that theperiphery of each annular discharge valve 19 likewise cooperates withits guard 31, in order that these valves will be constantly centralizedwith respect to their ports 17, 20, respectively, and the annular seriesof springs 30, 33 urge the valves 16, 19 toward their seats. It is alsonoteworthy that although the cylinder closure heads 21 are relativelythin and thus I reduce the compression clearance to a minimum, theseheads 21 are amply reinforced against possible distortion by the heavyguards 31 with which the heavy springs 34 coact; and the cap screws 29,35 enable the entire suction and discharge valve assemblages to beassembled externally of the frame 9 and applied as individual units tothe compressor in assembled condition or removed in like condition forinspection and possible renewal of worn or broken valves 16, 19.

The improved capacity control units 24 which coact with selected suctionvalves 16 for the. purpose of unloading the compressor are mounted upona partition 37 which spans the crankcase 10' but is subjected to suctionpressure on both sides, as shown in FIG. 2, but each of the units 24cooperates with both suction valves 16 of the selected pair of cylinders13 in the manner illustrated in FIGS. 3 to 6 inclusive. Each unloadingunit comprises in general a guide member 38 having thereon a centralbore 39 and four upright guide pins 40 disposed parallel to this borewhile two parallel upright pivot pins 41 are secured to the member 38between the guide pins 40; a plunger 42 reciprocable within the bore'39and having a rod 43 rising upwardly between the pivot pins 41; ahorizontal H-shaped yoke 44 penetrated by and "slidable along the pivotpins 41 and being constantly urged in an upward direction by relativelyheavy springs 45 surrounding the shorter guide pins 40 and coacting withthe member 38 and the yoke 44; a pair of levers 46 pivotally attached'to the upper ends of the pins 41 by pivots 47 and coacting at theiropposite ends with the plunger rod 43 and yoke 44 respectively; andmeans for transmitting motion of the yoke 44 to the adjacent suctionvalves 16 of the selected pair of compression cylinders and pistons.

Gas under pressure derived from the discharge chamber of the compressoror from any other source of control is admissible to the displacementchambers of the unloading unit plungers 42 through conduits 49, and arelatively light helical spring 50 coacts with the lower face of eachplunger in order to eliminate lost motion in the linkage. The laterallyprojecting four prongs or arms of the H-shaped yoke 44 extend todiametrically opposed sides of the adjacent pair of cylinders 13 asshown in FIG. 4, and the free ends of these arms are adapted to coactwith rings 51 which surround and are slidable along the adjacentcylinder walls and carry annular sets of parallel rods 52 reciprocablethrough parallel holes in the adjacent cylinder flanges 27 and which areengageable with the corresponding suction valves 16 to lift them fromtheir seats and hold them open during unloading operations. A helicalspring 53 surrounds each rod 52 between the adjacent cylinder flange 27and the ring 51, and each ring is recessed internally to provide a stop54 cooperable with a snap ring 55, in order to limit the downwardmovement of the adjacent ring 51 as clearly shown in FIG. 3.

With the various parts of the compressor constructed as hereinabovedescribed, the several cylinders 13 with the rings 51 and snap rings 55applied thereto may be pressed within the radially alined sets ofopenings in the frame 9 and properly positioned by means of stop rings57 as shown in FIGS. 2 and 3, and the pistons 14, connecting rods 15,crankshaft 11 and other accessories normally confined within thecrankcase 10' may be readily installed in an obvious manner upon removalof the cover plate 58. The capacity control units 24 may also be readilyinstalled through the radial outer frame openings and applied to thecylinders 13 with which they are to cooperate, before these cylindersare installed in the frame 9.

But the suction and discharge valve assemblages including the valves 16,19, the cylinder heads 21, the guides 28, 31, the light springs 30, 33,and the heavy springs 34 may be assembled on a workbench and applied ascomplete units to their respective cylinders 13 and secured in placewith the aid of the cap screws 29, and the covers 22 .and cap screws 35to finish the compressor installation. These valve assemblages may alsobe just as readily removed for inspection and possible replacement ofworn or broken valves16, 19, with minimum elfort and loss of time, andwhen assembled the valves 16, 19 will always be maintained properlycentralized with respect to their annular ports 17, 20 by the guides 28,31.

During normal operation of the improved compressor, the motor 12revolves the crankshaft 11 causing it to reciprocate the several sets ofpistons 14 in succession during each revolution of the cranks. Duringeach inward travel of the pistons 14, gas will be drawn from within thesuction chamber 10 through the ports 17 and past the suction valves 16into the corresponding displacement chambers 18; and when the compressoris operating at full capacity, outward travel of each piston 14 willcompress and deliver the gas admitted to its displacement chamber 18through the ports 20 and past the discharge valves 19 into the dischargeconduit 23. However, if the compressor is to be partially unloaded, thecapacity control units 24 will function to automatically hold thecorresponding suction valves 16 from their seats'during the dischargestroke of the adjacent pistons 14 thus preventing delivery of compressedgas from the cylinders 13 with which the units 24 cooperate.

From the foregoing description of the construction and operation of thedevices, it should be apparent that the present invention in factprovides an improved reciprocating piston type of gas compressor whichis simple and efiicient and wherein the various parts may be readilyassembled and installed or removed when necessary. The valves 16, 19 areeffectively guided to prevent lateral shifting, and each cylinder hasminimum clearance space thereby enhancing the efficiency of the unit,and the ports 17, 20 are usually formed as similar series of openings ina well-known manner. The improved capacity control units 24 are alsocompact and durable in structure and can be conveniently installed, andthe entire assemblage has proven highly satisfactory and successful incommercial use especially as applied to refrigeration systems.

I claim:

1. A gas compressor comprising, a main frame, a

cylinder mounted in said frame and having a bore and an integralexternal flange near an end of the bore provided with a series ofsuction ports and with a series of through holes, said cylinder alsohaving an annular external groove remote from said flange, a pistonreciprocable within said bore toward and away from said flanged cylinderend, an annular guide detachably secured to said flange, an annularsuction valve coacting with said guide and with said suction ports, aring slidable along the cylinder exterior and being provided with rodsmovable through said holes to lift the suction valve, an annular stopseated within the external groove of said cylinder to provide a seat forlimiting movement of said ring, a closure plate for said bore endloosely coacting with said suction valve guide and having therein aseries of discharge ports, a second annular guide secured to said plateand also loosely coacting with said suction valve guide, an annulardischarge valve coacting with said second guide and with said dischargeports, a cover cooperable with said frame to provide a compressed gaschamber, and resilient means interposed between said cover and saidsecond guide to detachably maintain said guides and said closure platein position, said guides coacting with said valves to prevent lateraldisplacement of the latter relative to their axes of annularity.

2. A gas compressor comprising, a main frame, a cylinder mounted in saidframe and having a bore and an integral external flange near an end ofthe bore provided with a series of parallel through holes and suctionports, a piston reciprocable within said bore toward and away from saidflanged cylinder end, an annular guide detachably secured to saidflange, an annular suction valve coacting with said guide and with saidsuction ports, a ring slidable along the cylinder exterior and havingthereon a series of parallel rods movable through said holes to lift thesuction valve, a closure plate for said bore end coacting with saidsuction valve guide and having therein a series of discharge ports, asecond annular guide secured to said plate and also coacting with saidsuction valve guide, an annular discharge valve coacting with saidsecond guide and with said discharge ports, a cover co operable withsaid frame to provide a compressed gas chamber, spring means interposedbetween said cover and said second guide to detachably maintain saidguides and said closure plate in position, and a capacity control unitcooperable with said ring to unload the compressor, said capacitycontrol unit including a yoke coacting with said ring and having guidemeans and an actuator for moving said yoke in a rectilinear path tothereby move said ring.

6 3. A gas compressor comprising, a main frame, a cylinder mounted insaid frame and having an end flange provided with suction ports and witha series of parallel holes and also having an annular external stopremote from the end flange, a piston reciprocable within said cylindertoward and away from said end, an annular suction valve vcooperable withsaid ports, a ring slidable along said cylinder and having a series ofparallel rods movable through said holes to lift said valve away fromsaid ports to unload the compressor, said ring being engageable withsaid stop, and being guided thereby throughout its range of movement,springs coacting with said ring to urge said rods away from said valve,a yoke cooperable with said ring to move said rods toward said valve,parallel stationary guide rods for said yoke, a fluid pressure actuatedplunger, and levers pivotally attached to said guide rods and beingswingable by said plunger to eflect movement of said ring in oppositionto said springs.

4. A gas compressor comprising, a main frame, a cylinder mounted in saidframe and having an end flange provided with suction ports and with aseries of parallel holes, a piston reciprocable Within said cylindertoward and away from said end, an annular suction valve coopcrable withsaid ports, a ring slidable along said cylinder and having a series ofparallel rods movable through said holes to lift said valve away fromsaid ports to unload the compressor, springs surrounding said rods andcoacting with said flange to urge the rods away from said valve, a yokecooperable with said ring to move said rods toward said valve, parallelstationary guide rods for said yoke, a fluid pressure actuated plungerdisposed between said guide rods, and levers pivotally attached to saidguide rods and being swingable about their pivots by said plunger tomove said yoke and thereby eflect movement of said ring in opposition tosaid springs.

References Cited by the Examiner UNITED STATES PATENTS 2,185,473 1/40Neeson 2303l 2,836,345 5/58 Gerteis 23031 3,071,309 1/63 Hackbart 230--FOREIGN PATENTS 160,230 12/54 Australia.

LAURENCE V. EFNER, Primary Examiner.

ROBERT M. WALKER, Examiner.

1. A GAS COMPRESSOR COMPRISING, A MAIN FRAME, A CYLINDER MOUNTED IN SAIDFRAME AND HAVING A BORE AND AN INTEGRAL EXTERNAL FLANGE NEAR AN END OFTHE BORE PROVIDED WITH A SERIES OF SUCTION PORTS AND WITH A SERIES OFTHROUGH HOLES, SAID CYLINDER ALSO HAVING AN ANNULAR EXTERNAL GROOVEREMOTE FROM SAID FLANGE, A PISTON RECIPROCABLE WITHIN SAID BORE TOWARDAND AWAY FROM SAID FLANGED CYLINDER END, AN ANNULAR GUIDE DETACHABLYSECURED TO SAID FLANGE, AN ANNULAR SUCTION VALVE COACTING WITH SAIDGUIDE AND WITH SAID SUCTON PORTS, A RING SLIDABLE ALONG THE CYLINDEREXTERIOR AND BEING PROVIDED WITH RODS MOVABLE THROUGH SAID HOLES TO LIFTTHE SUCTION VALVE, AN ANNULAR STOP SEATED WITHIN THE EXTERNAL GROOVE ANDSAID CYLINDER TO PROVIDE A SEAT FOR LIMITING MOVEMENT OF SAID RING, ACLOSURE PLATE FOR SAID BORE END LOOSELY COACTING WITH SAID SUCTION VALVEGUIDE AND HAVING THEREIN A SERIES OF DISCHARGE PORTS, A SECOND ANNULARGUIDE SECURED TO SAID PLATE AND ALSO LOOSELY COACTING WITH SAID SUCTIONVALVE GUIDE, AN ANNULAR DISCHARGE VALVE COACTING WITH SAID SECOND GUIDEAND WITH SAID DISCHARGE PORTS, A COVER COOPERABLE WITH SAID FRAME TOPROVIDE A COMPRESSED GAS CHAMBER, AND RESILIENT MEANS INTERPOSED BETWEENSAID COVER AND SAID SECOND GUIDE TO DETACHABLY MAINTAIN SAID GUIDES ANDSAID CLOSURE PLATE IN POSITION, SAID GUIDES COACTING WITH SAID VALVES TOPREVENT DISPLACEMENT OF THE LATTER RELATIVE TO THEIR AXES OF ANNULARITY.